1. Field of the Invention
The invention relates generally to an apparatus and method for providing access to items to be dispensed, and relates more particularly to the automatic dispensing of medical supplies. The invention further relates to an apparatus and method for reducing the amount of power consumed by an automatic dispensing system.
2. Description of the Related Art
In typical medical facilities (for example, hospitals, clinics, rest homes, etc), medical supplies are maintained in centralized storage locations and delivered to remote locations (for example, an emergency room, patient ward, etc.) as needed. Once delivered, the medical supplies are then dispensed to a patient. “Medical supply” is intended to include, among others, any item that is administered to or dispensed for a patient or used by a medical caregiver to treat a patient (for example, pharmaceuticals, syringes, sterilized bandages, scalpels, etc.). The invention has been described herein with reference to the dispensing of medical supplies, but it should be recognized that the invention is applicable to fields other than the medical field.
A variety of systems are used for transferring (i.e., from the storage location to the remote locations) and for dispensing (i.e., from the remote locations to the patient) the medical supplies. A system may use, for example, mobile dispensing carts which are stocked at the centralized storage area and then wheeled to the remote location. The medical supplies may then be dispensed directly from the mobile dispensing cart for administering to the patient. Alternatively, a dispensing system may use a stationary dispensing cabinet located at the remote location. Medical supplies are dispensed from the dispensing cabinet for later administering to the patient. A restocking cart, loaded with replacement medical supplies from the centralized storage location, is used to replenish the stationary dispensing cabinet.
Of particular interest to the present invention are dispensing systems which dispense items which require close monitoring and control. A variety of schemes have been proposed for providing secured access to items that are held within such dispensing systems, including locking the items within the carts or allowing access to only one item at a time (commonly referred to as “single dose” or “unit dose” dispensing). In addition to providing secure access, the schemes direct the user to the location within the dispensing system of the item to be dispensed.
One such system is described in related U.S. Pat. No. 5,745,366 entitled “Pharmaceutical Dispensing Device and Methods” and U.S. Pat. No. 5,905,653 entitled “Methods and Devices for Dispensing Pharmaceutical and Medical Supply Items.” The system controls access to items to be dispensed and maintains an inventory of the items. The system includes a dispensing unit having a plurality of storage locations distributed within an enclosure. The storage locations may include a multiplicity of lockable receptacles disposed within at least some of the storage locations. The storage locations and the individual lockable receptacles may have sensors and indicator lights associated therewith.
A processor is operable to receive user input and, in response to the input, is operable to activate an indicator light corresponding to the storage location associated with the item to be dispensed. The processor activates locks to prevent access to non-selected storage locations. The processor unlocks the individual receptacle (within the selected storage location) containing the item to be dispensed and activates the indicator light corresponding to the unlocked receptacle. The processor is also connected to receive feedback signals from the receptacle-associated sensors, such that when the unlocked receptacle is opened by a user, a feedback signal is sent to the processor indicating that the item has been dispensed.
Another such system is described in related U.S. Pat. No. 6,109,774 entitled “Drawer Operating System” and U.S. Pat. No. 6,065,819 entitled “Jerk-Resistant Drawer Operation System.” The patents disclose a drawer operating system for controlling a plurality of elongated drawers having a plurality of bins consecutive with one another along a sliding direction for holding various dispensable items. The drawers are housed in an array in a cabinet, each drawer arranged to move independently between a closed position and graduated, progressively opened positions to allow access to one or more bins and the contents stored therein. The system controls access to the bins by only allowing the drawer to travel the distance necessary to expose the next bin containing the item. For example, if a drawer has five bins each containing the desired item, the system will only allow the drawer to move to a position in which the first bin is exposed. After the first bin is emptied, the system will only allow the drawer to move to a position in which the second bin is exposed. The process may be repeated until all five bins are emptied. The system includes a keyboard for inputting coded information concerning the particular item needed and information as to the party entering the information.
U.S. Pat. No. 6,011,999 entitled “Apparatus for Controlled Dispensing of Pharmaceutical and Medical Supplies” discloses a system for controlled dispensing of pharmaceutical and medical supplies. The system includes a cabinet having a plurality of drawers, each having a plurality of receptacles. Each receptacle is sized to hold one item and has an identifier associated therewith. Locks are provided for securing the lid. The locks include an electrically responsive actuator wire, which in response to an electrical current supplied to the electrically responsive actuator wire, causes the lock to engage and disengage the lid. A processor is in communication with the locks and is configured to send a signal to the electrically responsive actuator wire to actuate the lid. The lid is spring biased and includes a colored indicator on an inner portion of the lid, such that when unlocked, the lid pops open and the indicator is exposed.
U.S. Pat. No. 6,116,461 entitled “Method and Apparatus for the Dispensing of Drugs” discloses another dispensing system. The system includes modular receptacles which are filled and transported to remote automatic dispensing machines for later retrieval and distribution. The system includes the loading, refilling, and replacement of the modular receptacles at various stages in the process of the invention. The system includes a receptacle having a lockable lid. When required an electronic circuit causes a latch to be actuated, thus opening the lockable lid. The lid has a spring in the hinge assembly which pushes the lid open when the latch is freed, thus indicating to the user the correct receptacle.
U.S. Pat. No. 5,520,450 discloses a supply station with an internal computer. The supply station is comprised of a cabinet having a plurality of lockable doors. Information is provided to the computer which unlocks the doors and simultaneously and automatically updates a patient's record, billing information and hospital inventory. Relevant data may be displayed on a display or printed on a sheet of paper by a printer connected to the computer.
U.S. Pat. No. 5,346,297 discloses an auxiliary storage and dispensing unit for use with a computer-controlled supply and medication dispenser station. The dispensing unit includes a cabinet having a plurality of lockable doors, a device for interconnecting one or more of the doors to allow access to the cabinet and a door unlocking device interconnected to the computer-controlled station for selectively unlocking one or more of the doors as a function of information inputted to the station.
Computer controlled dispensing systems, such as those discussed above, have been developed in response to a number of problems existing in medical facilities. Computer controlled dispensing systems, for example, address problems such as the removal of medications by unauthorized personnel, dispensing the wrong medication for a patient, inaccurate record keeping, etc.
The AcuDose-Rx dispensing cabinet available from McKesson Automation Inc. of Pittsburgh, Pa. is an example of a computer controlled cabinet programmed to address the aforementioned problems. A user is required to logon to the computer (thereby identifying who is removing medications). After identifying a patient, the user is presented with a list of medications that have been approved for administering to the identified patient (thereby addressing the problem of incorrect dispensing). Records are kept for each dispensing event thereby creating an audit trail.
As discussed above, a variety of different storage options are available for dispensing cabinets to ensure the safe and accurate dispensing and administration of medications. These include, but are not limited to, drawers with individual locking pockets which provide access to only one medication in a drawer at any given time; unit-dose dispensing drawers, which provide access to one “unit-of-use” of a medication at any given time, and open matrix drawers, which consist of a plurality of open pockets and which provide access to multiple medications at any given time.
While such systems provide for access controlled dispensing, most require large amounts of power to keep the compartments locked. Furthermore, systems using lighted indicators require additional power, control circuitry, and wiring. In contrast, systems using non-lighted indicators rely on the drawer or lid to “spring” open. If an item is caught on the drawer or lid, an increased risk is encountered that the item will become airborne when the drawer or lid is opened. The airborne item may become lost or may strike a user.
Thus, a need exists for a secure unit dose dispensing cabinet that requires less power to operate and provides a mechanical indicator means for notifying the user of correct location of the item to be dispensed without “springing” open a drawer or lid. Additionally, there exists a need for a safer, less error-prone dispensing and replenishment system.